In Eastern Europe, the E.U. faces a rebellion more threatening than Brexit

Members openly deride the bloc’s values, principles and rules. BUDAPEST — It was a continent-wide party to mark the end of history. On a spring night in 2004, a chorus sang in a Warsaw square. Beethoven’s “Ode to Joy” — the anthem of the European Union — echoed across once-bloody frontiers. Midnight fireworks sparkled along the Mediterranean. The next morning, organizers set a white-tablecloth breakfast on Budapest’s Chain Bridge for revelers still celebrating the dawn of a new era for Europe.